It is oftentimes desirable for the main wheels of a wheelchair to be locked as a patient either leaves, or attempts to be seated on, the wheelchair seat. For such purpose, wheel chairs have been provided in the past with conventional hand locks which allow the main wheels of the wheelchair to be locked. However, these conventional hand locks need to be set manually in order to be effective. Users may, however, sometimes forget to set the locks prior to use which might result in a potentially dangerous situation for the user.
Recently, locking devices have been disclosed in U.S. Pat. No. 5,203,433 (the entire content of which is expressly incorporated hereinto by reference, and referred to hereinafter as "the '433 patent") whereby the wheels of a wheel chair may be locked automatically in response to the user rising from the wheelchair seat. While the automatic locking devices disclosed in the '433 patent are satisfactory for their intended purpose, some improvements are still needed. For example, certain wheelchairs especially those having multiple axle locations for the main wheels--may not readily physically accommodate the devices disclosed in the '433 patent. Thus, it would be desirable if automatic wheelchair locking devices could be provided that is universally adaptable to a wide variety of wheelchair types. It is towards providing such wheelchair locking devices that the present invention is directed.
Broadly, the present invention is embodied in wheelchair locking devices which are automatically actuated in response to weight being removed from the wheelchair seat (i.e., when the user vacates the wheelchair). In preferred forms, the present invention is embodied in automatic locking systems for a wheelchair having a locking hub for attachment to a main wheel of the wheelchair, and a lock pin which is reciprocally rectilinearly moveable between locked and unlocked conditions with the lock hub. A rotary actuator is operatively coupled to the lock pin and is rotatable between normal and active positions which responsively causes the lock pin to move rectilinearly between its unlocked and locked positions, respectively.
A pivotal actuator lever is provided having one end positionable in close proximity to a seat of the wheelchair. The actuator lever is thus mounted for pivotal movements between raised and lowered conditions relative to the wheelchair seat. A flexible actuator cable connects a proximal end of the actuator lever and the rotary actuator. In operation, therefore, pivotal movement of the distal end of said actuator lever between its raised and lowered conditions responsively causes the actuator cable to rotate the rotary actuator between its normal and active conditions, respectively. As a result, the lock pin is caused to move to its locked position with the lock hub to thereby lock the main wheel of the wheelchair and prevent its rolling movement across the floor surface.
These, and other, aspects and advantages of the present invention will become more clear after careful consideration is given to the following detailed description thereof.